1. Field of the Invention
The present invention generally relates to an illuminating device capable of irradiating light from a light source in a predetermined light distribution pattern having a specified form and is adapted to be employed as a vehicle's headlamp and the like with especially clear cut lines of light distribution pattern.
2. Related Art
An example of conventional illuminating device is disclosed by the Japanese Patent laid-open No. H6-68702. The illuminating device is constructed for use on a vehicle, in which light from a single light source is branched by a plural number of optical fibres and conducted to lens bodies for light distribution toward the vehicle front area. Further, shades are used to obtain a light distribution pattern which is required for a vehicle. Using the shades in such a manner enables to obtain a desired light distribution pattern, to prevent a glare against drivers of vehicles running on the opposite lane while it can illuminate over a wide area extending even to the opposite lane in a short distance range.
However, with the abovementioned prior art, a cut line, i.e., a boundary between the illuminated area and the not illuminated area, may have been formed by shadows of shades but it could not provide sufficiently clear cut line. It is especially important that, for prevention of glare toward a vehicle driver on the opposite lane, the cut line at top or at the opposite lane side of the light distribution pattern is formed clearly.
Further, in the prior art, provision of a lens for concentrated (hot zone) light distribution pattern and a lens for flat light distribution pattern is proposed but it is necessary to coincide the cut lines at the top and at the opposite lane side of both lenses. Accordingly, the prior art proposes to coincide the cut lines of both lenses by moving the optical axis of one lens in parallel or by moving rotatablly, however, there still is a problem that the cut lines as a whole can not be made sufficiently clear because the cut lines of both lenses or one lens are not sufficiently clear.